FAREWELL LECTURE 273 



characterizing plants of Lower Gondwana, but, in addition, the 

 South African occurrences of associated animals, were also found 

 in the Permian deposits of Perm in north Russia. 



What then results is an exceedingly similar distribution of land 

 plants and land animals of that time, and a great continent in the 

 south; yet immediate proof of its continuity is lacking. 



In fact, only on the Pacific margins of this supposed or actually 

 united continent is it found that folding has taken place, and, indeed, 

 in the east of Australia and the west of South America; while the 

 intermediate Atlantic and Indian coasts are without younger folds. 

 It is true that more recently, folding of pre-Carboniferous time has 

 been described in South Africa, but in general the entire area between 

 the western South American Cordilleras and the eastern Australian 

 Cordilleras appears dead and unmovable. This is in contradis- 

 tinction to the great diversity in movements of the Northern Hem- 

 isphere. 



In general, these are the chains which we have sought to follow 

 in detail in the course of these two semesters. The attempt toward 

 a geometric arrangement of the mountain chains, which recently 

 has been undertaken by distinguished specialists, finds, I fear, but 

 little confirmation in actual occurrences. The tectonic hues that 

 are met in nature tend generally at most to follow straight lines 

 only in fissures or faults. The foldings, however, maintain them- 

 selves more like long waves, and they give way to the older horsts. 

 This is seen more clearly in the youngest Alps, or that branch of 

 the Altai trending toward Europe; the bows of the Banda Islands 

 are similar. 



I should now like to 'say a little about the conditions of hfe upon 

 the earth. We have already spoken of the wide distribution of 

 the land faunas and land floras of Lower Gondwana. Earlier types 

 of Carboniferous land floras had spread themselves from the Arctic 

 region to South Africa. The Culm flora is known in Europe, Mon- 

 golia, and Australia. Still more noteworthy is the fact that in the 

 basalt streams of western Greenland there are interbedded plant 

 layers of Lower and Middle Cretaceous, as well as of Tertiary times, 

 and that during all this period there lived in this Arctic region first 

 ferns and then leaf-bearing trees. In a word, in west Greenland 



